The invention relates generally to internal combustion engine blocks and, more particularly, to methods of casting such blocks.
In the past, it has been conventional to cast an engine block with integrally cast cylinders and with wall portions of an exhaust system and a water jacket. The exhaust system was completed by connecting to the block one or more exhaust manifold covers. The water jacket was completed by connecting to the engine block and/or manifold covers one or more water jacket cover. This arrangement has been particularly used in connection with the manufacture of multi-cylinder engines having equal length exhaust passages, as disclosed, for instance, in the Miller U.S. Pat. No. 3,692,006, issued Sept. 19, 1972.
In some engines, a portion of the exhaust system has been integrally cast into a block along the sides of the cylinders by using disposable cores. Such arrangements did not provide for equal length exhaust gas passages and also did not provide for encircling of the exhaust gas passages with a water jacket.
In another prior construction, disposable cores have been employed to provide integrally cast exhaust passages, but no provision was made for exhaust passages of equal length, or for an integrally cast water jacket encircling at least part of the exhaust gas passages.
Attention is also directed to U.S. Pat. No. 4,346,676 issued Aug. 31, 1982.